Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates to suspended luminaires designed to use linear fluorescent lamps to provide general lighting by illuminating the ceiling, and also provide a large luminous lens when viewed from below.
2. Background Art
With the recent proliferation of Video Display Terminals (VDTs) in the office environment, lighting designers have identified high contrast overhead lighting as a source of glare and reflection on VDT screens. Such glare and reflection is an undesirable effect which impacts worker comfort and productivity. Thus, the need has arisen for efficient low contrast illumination of the work environment.
Indirect linear fluorescent overhead lighting has been determined to be the most efficient means of illuminating a large office environment while providing low contrast illumination of the work area. Such lighting is accomplished by positioning linear fluorescent fixtures below the plane of the ceiling and directing light upward toward the ceiling. The light is then reflected off of the ceiling downward toward the room. Uniform illumination of the ceiling will provide low contrast lighting. Reflectors are used to produce wide distributions and permit short suspension distances.
Additionally, designers have found that eliminating glare does not in itself result in a pleasant environment. An appropriate perceived brightness has been found to be necessary to create comfort and a sense of well-being. Thus, lighting designers desire indirect luminaires having large luminous lens areas. Such large luminous lens areas are said to give the luminaire a xe2x80x98chandelierxe2x80x99 look.
A problem with prior art lumianires is that even illumination of large luminous lens areas has precluded the use of optical control elements, such as outboard kick reflectors, which may create shadows on the lens areas. Thus, the performance of the indirect component of such fixtures has suffered to provide the aesthetic benefit of the large luminous lens areas.
It is an object of the present invention to provide a suspended indirect linear fluorescent luminaire with a large luminous lens area having a wide optical distribution for a short suspension distance.
It is a further object of the present invention to provide a suspended indirect linear fluorescent luminaire having even illumination of large luminous lens areas and utilizing outboard kick reflectors, which does not have kick reflector shadows on the lens areas.
It is yet a further object of the present invention to provide a suspended indirect linear fluorescent luminaire having even illumination of large luminous lens areas and utilizing outboard kick reflectors which utilizes a parabolic reflector assembly under the tubular lamp to focus light toward the kick reflectors and toward the lens areas behind the kick reflectors.
These and other objects are achieved through the use of a suspended indirect linear fluorescent luminaire having a linear fluorescent lamp defining a central longitudinal axis for the optical system of the luminaire, or at least lamp sockets for such a lamp. The luminaire further has a parabolic reflector assembly having a pair of elongated reflectors, with each reflector having a substantially parabolic shaped cross section and being joined to form an apex parallel to and directly under the longitudinal axis of the lamp. The luminaire still further has a pair of lens members which are symmetrically arranged on either side of the longitudinal axis, with each lens member having an upper section inner portion longitudinal edge. Further still, the luminaire utilizes a pair of elongated kick reflector members, with each kick reflector member being supported along a different one of the lens member upper section inner portion longitudinal edges such that each of the substantially parabolic shaped reflectors redirects a portion of the light emitted by the underside of the linear fluorescent lamp toward the corresponding kick reflector member and toward the corresponding lens member upper section. Thus, the lenses may be illuminated in the shadow area behind the kick reflector members, and also have a wide optical distribution for a short suspension distance from the ceiling.